Ca. Peterson et al., MULTISTEP PROCESS-CONTROL AND CHARACTERIZATION OF SCANNING PROBE LITHOGRAPHY, Applied physics A: Materials science & processing, 66, 1998, pp. 729-733
An atomic force microscope with a conducting tip (CT-AFM) was used to
fabricate and characterize nanometer scale Lines of (1) silicon oxide
and (2) silicon nitride on II-terminated n-type silicon (100) wafers.
In process (1), a negative bias was applied to the tip of the CT-AFM s
ystem and the resulting electric held caused electrolysis of ambient w
ater vapor and local oxidation of the silicon surface. In addition, th
e accompanying current was detected by a sub-pA current amplifier. In
process (2), the presence of a nitrogen atmosphere containing a small
partial pressure of ammonia resulted in the local nitridation of the s
urface. The CT-AFM system was also used to locate and study the dielec
tric properties of the silicon-oxide lines as well as copper islands b
uried under 20 nm of silicon dioxide. A computer-controlled feedback s
ystem and raster scanning of the sample produced simultaneous topograp
hic and Fowler-Nordheim tunneling maps of the structures under study.
Detailed aspects of nanolithography and local-probe Fowler-Nordheim ch
aracterization using a CT-AFM will be discussed.